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Most often, the complex objects that we
manufacture today are made up of lots
of smaller, much less complex parts made
in bulk, then fastened together. Each of
those pieces needs to be cast or machined
or forged or milled, and then someone has
to assemble them. Additive manufactur-
ing is most intriguing because it makes
things holistically, with all the parts built
together as one, and can potentially trans-
form hundreds or even thousands of parts
into just a few. At the very least, this opens
up the possibility of much quicker proto-
types, which has the Army excited.
Mike Nikodinovski, mechanical engineer
and additive manufacturing expert in the
Materials Division at the U.S. Army Tank
Automotive Research, Development and
Engineering Center, said that an example
he often uses to demonstrate the differ-
ence between legacy manufacturing and
additive is a hole.
“If you drill a hole in a part,” he said,
“usually it’s in a straight line because that’s
the only thing that you can do with a drill,”
he said, “But additive doesn’t care about
that. If I want that hole to be twisty and
do different things, now, designers ... can
design for something different, because
the limitations of traditional manufac-
turing are gone. Now they can say, ‘I can
do all these crazy different things.’ ” That’s
one of the benefits, but also one of the
problems. Sometimes it makes sense to
do something completely outside any box
ever made, but other times, not so much.
It’s more than a radical change when
everything you know about how to design
and build an object are out the window.
“When you deal with a material that’s
been forged or cast for centuries, there
are a lot of assumptions built into the
selection of the material and the manu-
facturing method,” said Dr. William
Benard, senior campaign scientist in
materials development with the U.S.
Army Research Laboratory (ARL) in
Adelphi, Maryland. According to Benard,
ARL’s research and development portfo-
lio is divided into campaigns that reflect
the A rmy’s priorities. Senior campaign
scientists work across the organization
to develop and coordinate research strat-
egy and to communicate and interface
with the broader research communi-
ties—DOD, national labs, industry and
academia.
That deep institutional and engineering
muscle memory in manufacturing simply
does not exist in additive, which has only
been with us since the mid-1980s. That’s
not much more than a couple of ticks of
the historical clock compared with the
thousands of years that humans have
been casting, forging, cutting, milling
and drilling.
“That’s where we really have to do the
research to understand how the materi-
als behave differently,” Benard said. “It’s
not that they’re so fundamentally differ-
ent, it’s just building up the knowledge
base that we have with other manufactur-
ing methods.”
Not only that, said Benard, “I think the
scale of the design space that is opened
up makes it very challenging to develop
good intuition. This is one of the areas we
are working on—design tools to manage
complexity and help identify non-intuitive
optimal designs. The tools have to address
the complexity of selecting and placing
different materials in a volume, or modu-
lating the material properties, to satisfy
constraints and performance objectives
that exist in multiple intersecting fields
and dimensions—for example, looking
WIDE ARRAY
These parts were made using additive manu-
facturing, which creates plastic items and
other durable components by adding material,
layer by layer, using 3D printers. Depend-
ing on the process used, wire, polymer
filament, powders, liquids, gels, mixtures
of glues and materials, and slurries can
produce components. (U.S. Army photo)
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SCIENCE&TECHNOLOGY